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Can anyone explain these questions from ADA OAT practice test? My test is in two days so if anyone can help explaining these questions that would be great!!
(Ignore physics questions unless you know them!)
http://www.ada.org/~/media/oat/files/oat_sample_test.ashx
This is for OAT but it's a good practice test for DAT as well.
Gen Chem Questions
44. If the mass percent of oxygen in a nitrogenoxygen compound is known, given the mass percent of oxygen, all of the following are needed to determine the molecular formula of a nitrogen-oxygen compound EXCEPT one. Which one is this EXCEPTION?
A. Atomic mass of nitrogen B. Atomic mass of oxygen C. Avogadro's number D. Empirical formula E. Molar mass of the compound
The answer is D. (This might be an error and the answer is C.. )
61. A 0.60 M solution is made by dissolving solid compound X in water. After ten seconds, the concentration of X is 0.40 M. All of the following could account for these results EXCEPT one. Which one is this EXCEPTION?
A. Precipitation B. Neutralization C. Evaporation D. Decomposition E. Disproportionation
The answer is A. (The answer might be C...?)
69. Carbon tetrachloride, CCl4 , is observed to have a higher boiling point than chloroform, CHCl3 . All of the following statements are true base on this observation EXCEPT one. Which is this EXCEPTION?
A. Dispersion forces are experienced by CCl4 and CHCl3 .
B. At a given temperature, the vapor pressure of CCl4 is less than that of CHCl3 .
C. The molar heat of vaporization of CCl4 is greater than that of CHCl3 .
D. Dipole-dipole interactions are responsible for the larger boiling point of CCl4 .
The answer is D. (Why not C?)
OChem
76. Nitration of toluene (Ph–CH3 ) with HNO3 /H2 SO4 occurs
A. faster than nitration of benzene and produces mostly ortho and para products.
B. slower than nitration of benzene and produces mostly meta product.
C. faster than nitration of benzene and produces mostly meta product.
D. slower than nitration of benzene and produces mostly ortho and para products.
E. at the same rate as nitration of benzene and produces mostly meta product.
The answer is D (I don't understand why it is faster. How do you know if it is faster or slower?)
84. Which of the following compounds best fits the 1H NMR spectral data listed below?
(Sorry I cannot post the image.)
The answer is B. (This is very confusing to me. please help!)
88. Which of the following statements is true regarding a pair of compounds that are diastereomers of each other?
A. They are configurational isomers.
B. They have the same physical properties.
C. They are mirror images.
D. They are always optically active.
E. They have equal but opposite alpha values.
The answer is A. (why??)
93. What is the hybridization of a nitrogen atom if it forms two sigma two pi bonds?
A. sp B. sp2 C. sp3 D. sp3d 2
The answer is C. (or A?)
Physics
#26 The water in a swimming pool is 3.0 m deep. During the day, the atmospheric pressure increases by 2.0 x 103 N/m2 . During this same period, the pressure at the bottom of the pool, in N/m2 , will
A. not change. B. increase by 1.0 x 10^7 . C. increase by 6.0 x 10^3 . D. increase by 6.0 x 10^4 . E. increase by 2.0 x 10^3 . The answer is E.
#39. What is the focal length in cm of a lens that produces an image 30 cm behind it when the object is placed 6 cm in front of it? A. 7.5 B. 36 C. 5.0 D. 24 E. 18.0
The answer is C. (I guess an image behind lens would be positive to get this answer. Can anyone explain when you use positive and negative? )
Thanks!!
(Ignore physics questions unless you know them!)
http://www.ada.org/~/media/oat/files/oat_sample_test.ashx
This is for OAT but it's a good practice test for DAT as well.
Gen Chem Questions
44. If the mass percent of oxygen in a nitrogenoxygen compound is known, given the mass percent of oxygen, all of the following are needed to determine the molecular formula of a nitrogen-oxygen compound EXCEPT one. Which one is this EXCEPTION?
A. Atomic mass of nitrogen B. Atomic mass of oxygen C. Avogadro's number D. Empirical formula E. Molar mass of the compound
The answer is D. (This might be an error and the answer is C.. )
61. A 0.60 M solution is made by dissolving solid compound X in water. After ten seconds, the concentration of X is 0.40 M. All of the following could account for these results EXCEPT one. Which one is this EXCEPTION?
A. Precipitation B. Neutralization C. Evaporation D. Decomposition E. Disproportionation
The answer is A. (The answer might be C...?)
69. Carbon tetrachloride, CCl4 , is observed to have a higher boiling point than chloroform, CHCl3 . All of the following statements are true base on this observation EXCEPT one. Which is this EXCEPTION?
A. Dispersion forces are experienced by CCl4 and CHCl3 .
B. At a given temperature, the vapor pressure of CCl4 is less than that of CHCl3 .
C. The molar heat of vaporization of CCl4 is greater than that of CHCl3 .
D. Dipole-dipole interactions are responsible for the larger boiling point of CCl4 .
The answer is D. (Why not C?)
OChem
76. Nitration of toluene (Ph–CH3 ) with HNO3 /H2 SO4 occurs
A. faster than nitration of benzene and produces mostly ortho and para products.
B. slower than nitration of benzene and produces mostly meta product.
C. faster than nitration of benzene and produces mostly meta product.
D. slower than nitration of benzene and produces mostly ortho and para products.
E. at the same rate as nitration of benzene and produces mostly meta product.
The answer is D (I don't understand why it is faster. How do you know if it is faster or slower?)
84. Which of the following compounds best fits the 1H NMR spectral data listed below?
(Sorry I cannot post the image.)
The answer is B. (This is very confusing to me. please help!)
88. Which of the following statements is true regarding a pair of compounds that are diastereomers of each other?
A. They are configurational isomers.
B. They have the same physical properties.
C. They are mirror images.
D. They are always optically active.
E. They have equal but opposite alpha values.
The answer is A. (why??)
93. What is the hybridization of a nitrogen atom if it forms two sigma two pi bonds?
A. sp B. sp2 C. sp3 D. sp3d 2
The answer is C. (or A?)
Physics
#26 The water in a swimming pool is 3.0 m deep. During the day, the atmospheric pressure increases by 2.0 x 103 N/m2 . During this same period, the pressure at the bottom of the pool, in N/m2 , will
A. not change. B. increase by 1.0 x 10^7 . C. increase by 6.0 x 10^3 . D. increase by 6.0 x 10^4 . E. increase by 2.0 x 10^3 . The answer is E.
#39. What is the focal length in cm of a lens that produces an image 30 cm behind it when the object is placed 6 cm in front of it? A. 7.5 B. 36 C. 5.0 D. 24 E. 18.0
The answer is C. (I guess an image behind lens would be positive to get this answer. Can anyone explain when you use positive and negative? )
Thanks!!
